I am on hold with Cummings regarding Rotella, but here is a Cummings service bulletin regarding oil:
This Service Bulletin outlines the proper application and maintenance of engine oil for Cummins® engines. The purpose of this Service Bulletin is to update and simplify Cummins Inc. recommendations and guidelines for the end user. Cummins Inc. recommends the use of a high quality, diesel engine oil such as Valvoline Premium Blue® or Valvoline Premium Blue Extreme Life® or their equivalent, and high quality filters such as Fleetguard® or their equivalent. Cummins Inc. bases oil drain recommendations on oil performance classifications and duty cycle. Maintaining the correct oil and filter change interval is a vital factor in preserving the integrity of an engine. Consult your Operation and Maintenance manual for detailed instructions on determining the oil change interval for your engine.
Synthetic Oils Use of “synthetic engine oils” (those made with API group 3 or group 4 base stocks) is permitted subject to the same performance and viscosity limitations of petroleum (mineral) based engine oils. The same oil change intervals must be applied to synthetic oils that are applied to petroleum (mineral) based engine oils. Re-refined Oils Re-refined lubricating oils can be used in Cummins® engines, if they have an API license signifying they have been tested and meet the minimum standards for that quality level. It is important to be certain these oils are actually re-refined and not just reclaimed. Re-refined oils have been treated to remove additives and wear debris, distilled, and refortified with additives. Friction Modifiers Do not use oils containing supplemental friction modifiers in Cummins® diesel engines unless the oil supplier can provide evidence of satisfactory performance in Cummins® engines. Obtain the oil supplier's commitment that they will make sure the oil is satisfactory, or do not use the product.
Some oil suppliers might claim better fuel economy for the lower viscosity oils. Lower viscosity results in lower oil film thickness. Therefore, Cummins Inc. has required that all multi-viscosity 30 weight (xW30) oils registered under CES 20078 (API CI-4) must meet the minimum High Temperature / High Shear viscosity of 3.5 cSt. These can be used over a wider temperature range than other 10W30 or 5W30 oils. As these oils will have directionally thinner oil films than 15W40 oils, top quality Fleetguard® filters must be used above 20°C [70°F]. See Figure 1 for viscosity recommendations.
Viscosity Recommendations Cummins Inc. recommends the use of multigrade lubricating oils with viscosity grades shown in Figure 1 for the ambient temperatures indicated. Only the preferred oil grades are shown in the figure. If monograde oils are substituted for multigrade oils in the areas where multigrades are not currently available, shortened drain intervals might be required, as determined by close monitoring of the oil condition with scheduled oil sampling. Use of monograde oils can affect engine oil control.
Section 7: OIL FILTRATION Oil Filter Design, Use and Function Maximum engine life is dependent on the correct use and maintenance of full flow, bypass, or combination lubricating oil filters that protect vital engine components from the abrasive contaminant, which are held in suspension in the lubricating oil. Cummins Inc. requires the use of full flow filters on all of its engine models. In addition, except for the B Series model, all turbocharged Cummins® engines must use bypass filtration, bypass filtration is strongly recommended for use on all naturally aspirated engines. The full flow filter will remove contaminant particles of 30 microns and larger that are suspended in the engine oil. Particles of this size can cause immediate bearing damage. The bypass filter (or filter section if using a combination filter) receives approximately ten percent of the total pump output and filters it to remove smaller particles, down to 10 microns, which the full flow filter does not capture. This maintains the oil contaminant concentration at a level low enough to prevent engine wear. Cummins® engines are fitted at the factory with a quality Fleetguard® combination lubricating oil filter, which contains both a full flow and bypass filter in one filter can. Many of them are a Venturi® design which directs all of the oil flow to vital engine parts, instead or returning a portion of it to the pan. These filters provide the optimum balance of fine filtration for protection and rugged construction designed for long filter life. Some Cummins® engines are being supplied with a Fleetguard Centriguard™ centrifugal filter using ConeStaC™ technology. These are the only centrifugal filters demonstrated in laboratory testing to surpass Fleetguard's stacked disk bypass filters. Any add-on filtration system must meet all applicable application guidelines.